app.py

import os
import logging
import gradio as gr
from huggingface_hub import InferenceClient

# Configure logging
logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s | %(levelname)s | %(message)s",
    datefmt="%Y-%m-%d %H:%M:%S",
)
logger = logging.getLogger(__name__)

# Environment variables for configuration
HF_TOKEN = os.environ.get("HF_TOKEN", "")

logger.info(f"HF_TOKEN configured: {bool(HF_TOKEN)}")

client = InferenceClient(token=HF_TOKEN) if HF_TOKEN else InferenceClient()
logger.info("InferenceClient initialized")


# Language pairs with their MarianMT models (configurable via env vars)
LANGUAGE_PAIRS = {
    "English → French": os.environ.get("MODEL_EN_FR", "Helsinki-NLP/opus-mt-en-fr"),
    "English → Spanish": os.environ.get("MODEL_EN_ES", "Helsinki-NLP/opus-mt-en-es"),
    "English → German": os.environ.get("MODEL_EN_DE", "Helsinki-NLP/opus-mt-en-de"),
    "French → English": os.environ.get("MODEL_FR_EN", "Helsinki-NLP/opus-mt-fr-en"),
    "Spanish → English": os.environ.get("MODEL_ES_EN", "Helsinki-NLP/opus-mt-es-en"),
    "German → English": os.environ.get("MODEL_DE_EN", "Helsinki-NLP/opus-mt-de-en"),
}
logger.info(f"Loaded {len(LANGUAGE_PAIRS)} language pairs")


def translate(text: str, language_pair: str) -> str:
    """Translate text using selected language pair."""
    logger.info(f"translate() called | text_len={len(text)} | pair={language_pair}")
    
    if not text.strip():
        logger.warning("Empty text received")
        return "📝 Enter text to translate!"
    
    try:
        model = LANGUAGE_PAIRS[language_pair]
        logger.info(f"Calling translation | model={model}")
        result = client.translation(text, model=model)
        logger.info(f"Translation: {result.translation_text[:50]}...")
        return result.translation_text
    except Exception as e:
        logger.error(f"API error: {e}")
        return f"❌ Error: {e}"


logger.info("Building Gradio interface...")

with gr.Blocks(title="Instant Translator") as demo:
    gr.Markdown("# 🌍 Instant Translator\nTranslate text between languages instantly!")

    with gr.Row(equal_height=True):
        with gr.Column():
            input_text = gr.Textbox(
                label="Source text",
                placeholder="Hello, how are you today?",
                lines=4,
                autofocus=True,
            )
            language_pair = gr.Dropdown(
                choices=list(LANGUAGE_PAIRS.keys()),
                value="English → French",
                label="Language pair",
            )
            btn = gr.Button("Translate 🚀", variant="primary")

        with gr.Column():
            output_text = gr.Textbox(
                label="Translation",
                lines=4,
                interactive=False,
            )

    btn.click(translate, inputs=[input_text, language_pair], outputs=output_text)
    input_text.submit(translate, inputs=[input_text, language_pair], outputs=output_text)

    gr.Examples(
        examples=[
            ["Hello, how are you today?", "English → French"],
            ["Machine learning is fascinating.", "English → Spanish"],
            ["I love programming with Python.", "English → German"],
        ],
        inputs=[input_text, language_pair],
    )

demo.queue()
logger.info("Starting Gradio server...")
demo.launch()